全文获取类型
收费全文 | 199116篇 |
免费 | 14174篇 |
国内免费 | 685篇 |
专业分类
耳鼻咽喉 | 2504篇 |
儿科学 | 5258篇 |
妇产科学 | 3110篇 |
基础医学 | 26141篇 |
口腔科学 | 3192篇 |
临床医学 | 20483篇 |
内科学 | 42318篇 |
皮肤病学 | 2757篇 |
神经病学 | 19317篇 |
特种医学 | 7126篇 |
外国民族医学 | 4篇 |
外科学 | 30136篇 |
综合类 | 2732篇 |
现状与发展 | 1篇 |
一般理论 | 253篇 |
预防医学 | 16707篇 |
眼科学 | 4789篇 |
药学 | 13783篇 |
2篇 | |
中国医学 | 260篇 |
肿瘤学 | 13102篇 |
出版年
2023年 | 1042篇 |
2022年 | 1545篇 |
2021年 | 4359篇 |
2020年 | 2506篇 |
2019年 | 4117篇 |
2018年 | 4734篇 |
2017年 | 3494篇 |
2016年 | 3764篇 |
2015年 | 4530篇 |
2014年 | 6495篇 |
2013年 | 9188篇 |
2012年 | 13900篇 |
2011年 | 14704篇 |
2010年 | 8191篇 |
2009年 | 7557篇 |
2008年 | 13047篇 |
2007年 | 13780篇 |
2006年 | 13204篇 |
2005年 | 13476篇 |
2004年 | 12546篇 |
2003年 | 12016篇 |
2002年 | 11196篇 |
2001年 | 1756篇 |
2000年 | 1310篇 |
1999年 | 1774篇 |
1998年 | 2460篇 |
1997年 | 1986篇 |
1996年 | 1616篇 |
1995年 | 1552篇 |
1994年 | 1323篇 |
1993年 | 1336篇 |
1992年 | 996篇 |
1991年 | 890篇 |
1990年 | 842篇 |
1989年 | 781篇 |
1988年 | 724篇 |
1987年 | 667篇 |
1986年 | 671篇 |
1985年 | 802篇 |
1984年 | 1005篇 |
1983年 | 974篇 |
1982年 | 1386篇 |
1981年 | 1274篇 |
1980年 | 1107篇 |
1979年 | 555篇 |
1978年 | 687篇 |
1977年 | 642篇 |
1976年 | 518篇 |
1975年 | 466篇 |
1974年 | 412篇 |
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
51.
Rotary ventricular assist devices (VADs) are less sensitive to preload than the healthy heart, resulting in inadequate flow regulation in response to changes in patient cardiac demand. Starling‐like physiological controllers (SLCs) have been developed to automatically regulate VAD flow based on ventricular preload. An SLC consists of a cardiac response curve (CRC) which imposes a nonlinear relationship between VAD flow and ventricular preload, and a venous return line (VRL) which determines the return path of the controller. This study investigates the importance of a physiological VRL in SLC of dual rotary blood pumps for biventricular support. Two experiments were conducted on a physical mock circulation loop (MCL); the first compared an SLC with an angled physiological VRL (SLC‐P) against an SLC with a vertical VRL (SLC‐V). The second experiment quantified the benefit of a dynamic VRL, represented by a series of specific VRLs, which could adapt to different circulatory states including changes in pulmonary (PVR) and systemic (SVR) vascular resistance versus a fixed physiological VRL which was calculated at rest. In both sets of experiments, the transient controller responses were evaluated through reductions in preload caused by the removal of fluid from the MCL. The SLC‐P produced no overshoot or oscillations following step changes in preload, whereas SLC‐V produced 0.4 L/min (12.5%) overshoot for both left and right VADs. Additionally, the SLC‐V had increased settling time and reduced controller stability as evidenced by transient controller oscillations. The transient results comparing the specific and standard VRLs demonstrated that specific VRL rise times were improved by between 1.2 and 4.7 s ( = 3.05 s), while specific VRL settling times were improved by between 2.8 and 16.1 seconds ( = 8.38 s) over the standard VRL. This suggests only a minor improvement in controller response time from a dynamic VRL compared to the fixed VRL. These results indicate that the use of a fixed physiologically representative VRL is adequate over a wide variety of physiological conditions. 相似文献
52.
M. Larsabal S. Ly E. Sbidian M. Moyal-Barracco J.-N. Dauendorffer N. Dupin M.A. Richard O. Chosidow M. Beylot-Barry 《The British journal of dermatology》2019,180(3):647-656
Psoriasis is a common chronic inflammatory skin disease, affecting about 3% of the general population and approximately 2.5 million people in France, where this study took place. The genital area may be affected, however prevalence is poorly understood, meaning we do not know exactly how commonly this occurs. While it affects quality of life, genital psoriasis is under-recognized, probably due to the reluctance of patients to discuss genital involvement and sexual quality of life. The aims of this study, called the GENIPSO study, were to determine the prevalence of genital psoriasis, its clinical characteristics (its symptoms), whether it is associated with a particular type of psoriasis, and its impact on quality of life. The study included 776 adults seeing their doctor for psoriasis between November 2016 and March 2017. Among them, 336 (43.2%) had genital psoriasis. All these patients were aware that they had psoriasis on their genitals (genital lesions) but only 135 (40%) had already had a genital medical examination. Genital lesions were associated with (linked to) male gender, more severe psoriasis, first developing psoriasis when aged over 20 years, psoriasis of the skin folds, psoriasis on the scalp, nail and external auditory (ear) canal, but they were not associated with obesity or psoriatic arthritis. Itching was the main symptom. Genital psoriasis was associated with reduced quality of life and sexual health. The study found that genital psoriasis has a high prevalence in patients seeing their doctors about their psoriasis generally, it affects quality of life and should be better taken into account by dermatologists for the best possible care for patients. 相似文献
53.
54.
Children with autism spectrum disorder (ASD) demonstrate limited playfulness. Their difficulty engaging in meaningful interaction with others renders playful engagement in social interactions a challenge. Although little direct evidence exists regarding the promotion of these children’s playful engagement, links can be established with many traits cited in play and social interaction studies. This paper presents the results of a conceptual clarification exercise regarding the key behaviours associated with the construct of playful engagement in preschool-aged children with ASD. Behaviours were identified based on hallmark deficits in early social interactions and play of children with ASD. The analysis revealed the following behaviours: positive affect, engagement, imitation, joint attention, initiation of social interaction, social responsiveness, flexibility, child’s laughter in funny situations and giving and reading non-verbal cues. In conclusion, a conceptually coherent stage has been set for exploring the literature regarding interventions to promote the playful engagement of preschool-aged children with ASD. 相似文献
55.
56.
57.
Hanna Lee Mary K. Tan Andrew T. Yan Paul Angaran Paul Dorian Claudia Bucci Jean C. Gregoire Alan D. Bell Martin S. Green Peter L. Gross Allan Skanes Charles R. Kerr L. Brent Mitchell Jafna L. Cox Vidal Essebag Brett Heilbron Krishnan Ramanathan Carl Fournier Shaun G. Goodman 《The Canadian journal of cardiology》2019,35(2):160-168
Background
Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.Methods
We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).Results
Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.Conclusions
Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation. 相似文献58.
59.
Aurora Perez-Cornago Georgina K. Fensom Colm Andrews Eleanor L. Watts Naomi E. Allen Richard M. Martin Mieke Van Hemelrijck Timothy J. Key Ruth C. Travis 《British journal of cancer》2020,123(12):1808
Background Although prostate cancer is a leading cause of cancer death, its aetiology is not well understood. We aimed to identify novel biochemical factors for prostate cancer incidence and mortality in UK Biobank.Methods A range of cardiovascular, bone, joint, diabetes, renal and liver-related biomarkers were measured in baseline blood samples collected from up to 211,754 men at recruitment and in a subsample 5 years later. Participants were followed-up via linkage to health administrative datasets to identify prostate cancer cases. Hazard ratios (HRs) and 95% confidence intervals were calculated using multivariable-adjusted Cox regression corrected for regression dilution bias. Multiple testing was accounted for by using a false discovery rate controlling procedure.Results After an average follow-up of 6.9 years, 5763 prostate cancer cases and 331 prostate cancer deaths were ascertained. Prostate cancer incidence was positively associated with circulating vitamin D, urea and phosphate concentrations and inversely associated with glucose, total protein and aspartate aminotransferase. Phosphate and cystatin-C were the only biomarkers positively and inversely, respectively, associated with risk in analyses excluding the first 4 years of follow-up. There was little evidence of associations with prostate cancer death.Conclusion We found novel associations of several biomarkers with prostate cancer incidence. Future research will examine associations by tumour characteristics.Subject terms: Predictive markers, Prostate cancer, Risk factors 相似文献
60.
Auda A. Eltahla Fabio Luciani Peter A. White Andrew R. Lloyd Rowena A. Bull 《Viruses》2015,7(10):5206-5224
The hepatitis C virus (HCV) is a pandemic human pathogen posing a substantial health and economic burden in both developing and developed countries. Controlling the spread of HCV through behavioural prevention strategies has met with limited success and vaccine development remains slow. The development of antiviral therapeutic agents has also been challenging, primarily due to the lack of efficient cell culture and animal models for all HCV genotypes, as well as the large genetic diversity between HCV strains. On the other hand, the use of interferon-α-based treatments in combination with the guanosine analogue, ribavirin, achieved limited success, and widespread use of these therapies has been hampered by prevalent side effects. For more than a decade, the HCV RNA-dependent RNA polymerase (RdRp) has been targeted for antiviral development. Direct acting antivirals (DAA) have been identified which bind to one of at least six RdRp inhibitor-binding sites, and are now becoming a mainstay of highly effective and well tolerated antiviral treatment for HCV infection. Here we review the different classes of RdRp inhibitors and their mode of action against HCV. Furthermore, the mechanism of antiviral resistance to each class is described, including naturally occurring resistance-associated variants (RAVs) in different viral strains and genotypes. Finally, we review the impact of these RAVs on treatment outcomes with the newly developed regimens. 相似文献